Temperature controlling means for ovens and the like



Jan. 9, 1968 F. J. FQRTE 3,362,635

TEMPERATURE CONTROLLING MEANS FOR OVENs AND THE LIKE original filedApril l1.2, 1962 s sheets-sheet 1 I lll! l IIIHIHI N o l o Q Q q- CQ'INVENTOR.

` FRANCIS J. FORTE FIG-l l Jan. 9, 196s- F. J. FQRTE 3,362,635

v TEMPERATURE CONTROLLING MEANS FOR OVENS AND THE LIKE original FiledApril 12, 1932 8 Shee'sfsheet INVENTOR. FRANCIS J. FORTE Jan. 9, 1968 F.J. FORTE 3,362,635

E TEMPERATURE CONTROLLING MEANS FOR OVENS AND THE LIKE Original FiledApril l2, 1962 8 Sheets-Sheet 3 FRANC IS J. FORTE F. J. FORTE Jan. 9,1968 TEMPERATURE CONTROLLING MEANS FOR OVENS AND THE LIKE original FiledApril 12, 1962 INVENTOR. FRANCIS J. FORTE l/Ov Jan'. 9, 1968 F. J. FORTE3,362,635

TEMPERATURE CONTROLLING MEANS FOR OVENS AND THE LIKE A Original FiledApril l2., 1962 8 Sheets-Sheet 5 FIG-Il INVENTOR. FRANCIS J. FORTE Jan.9, 1968 F. FORTE 3,362,635

`TEMPERATURE `CONTROLLING MEANS FOR OVENS AND THE I LULF Original FiledApril 12,41962 BShQetS-Sheet 6 INVENTOR. FRANCIS J4 FORTE Jan. 9, 1968F; J. FORTE 3,362,635

TEMPERATURE CONTROLLING MEANS FOR OVENS AND THE LIKE original FiledApril '12, 1962 8 Sheetssheet INVENTOR. FRANCIS J.` FORTE F. J. FORTE3,362,635

TEMPERATURE CONTROLLING MEANS FOR OVENS AND THE LIKE Jan. 9, 1968 8Sheets-Sheet B Original Filed April 12, 1962 INVENTOR.

FRANIS J. FORTE United States Patent O 3,362,635 TEMPERATURE CONTROLLINGMEANS FOR OVENS AND THE LIKE Francis J. Forte, New Haven, Conn.,assignor to Robertshaw Controls Company, a corporation of DelawareApplication July 21, 1965, Ser. No. 480,227, now Patent No. 3,304,001,dated Feb. 14, 1967, which is a continuation of abandoned applicationSer. No. 186,909, Apr. 12, 1962. Divided and this application Jan. 30,1967, Ser. No. 612,674

10 Claims. (Cl. 236-46) ABSTRACT F THE DISCLOSURE This disclosurerelates to a control means for a domestic oven or the like wherein thecontrol means includes a frame means rotatably carrying a collar adaptedto telescopically receive a control shaft of a thermostatic devicewhereby the thermostatic device can be manually set to control thetemperature in the oven, the control device including means forautomatically rotating the collar and interconnected control shaft ofthe thermostat to a lower temperature setting after the occurrence ofthe event, such as the lapse of a predetermined time period, whereby thecontrol device will maintain the temperature in the oven at the reducednon-cooking and warmth retaining temperature until the housewife or thelike manually turns the control device to its Off position.

This application is a divisional patent application of its copendingparent application, Serial Number 480,227, tiled July 21, 1965, now U.S.Patent No. 3,304,001, which, in turn, is a continuation application,Serial Number 186,909, led April 12, 1962, now abandoned.

This invention relates to an improved oven or burner control device aswell as to an improved method of operating such oven or burner.

Heretofore, conventional domestic ovens or the like of either theelectric or gas type have been provided with automatic timer means sothat the housewife or the like can place food in the oven at any oneperiod of the day and have the oven automatically come on at a set timeof the day and cook the food at a selected temperature for a selectedtime interval while the housewife is away.

However, if the period of time that the food must remain in the ovenbefore the oven cooks the same is relatively long, food spoilage canoccur. Further, should the housewife be late in returning, the cookedfood has cooled and requires further heating thereof before the same canbe served.

According to the teachings of this invention, however, an improvedcontrol device is provided whereby food can be placed in the oven andthe housewife can select the desired length of time that the food is tobe cooked at a desired temperature whereby the food will be immediatelycooked by the oven during the desired time interval so that no foodspoilage will occur.

Thereafter, the control device of this invention automatically reducesthe temperature of the oven to a predetermined temperature, such as awarming and noncooking temperature, whereby the food can remain in theoven until served, the food being held at a serving temperature by thecontrol device of this invention.

The control device of this invention is so constructed and arranged thatthe control device is readily adapted to be interconnected toconventional thermostatic devices utilized to control conventional ovenburners and the like whereby the control devices of this invention canbe manufactured by one manufacturer and can be utilized by various ovenmanufacturers with their particular thermostatic devices.

3,362,635 Patented Jan. 9, 1968 f5 ICC Further, the control device ofthis invention is so designed that the housewife or the like can Changethe temperature setting to a lower temperature after the requiredcooking hours have been set or part of the cooking time has beencompleted.

In addition, the control device of this invention is so constructed andarranged that the control device can be utilized in a conventionalmanner for cooking purposes without utilizing the aforementionedautomatic lower temperature feature.

Accordingly, it is an object of this invention to provide an improvedcontrol device having one or more of the novel features set forth aboveor hereinafter shown or described.

Another object of this invention is to provide an improved method ofoperation of an oven, burner or the like.

Other objects, uses and advantages of this invention are apparent from areading of this description which proceeds with reference to theaccompanying drawings forming a part thereof and wherein:

FIGURE 1 is a front view of the improved control device of thisinvention.

FIGURE 2 is a top View of the control device of FIG- URE 1.

FIGURES 3-6 are respectively front views of other control devices ofthis invention having the various control parts thereof disposed indifferent positions relative to each other.

FIGURE 7 is a fragmentary, partially exploded, top cross-sectional Viewdisclosing the method of interconnecting a thermotat device to thecontrol device of this invention.

FIGURE 8 is an exploded perspective view illustrating certain parts ofthe structure illustrated in FIGURE 7.

FIGURE 9 is a front View of the control device of FIGURE 1 with thecontrol panel thereof removed.

FIGURE 10 is a rear view of the control device of FIGURE 1 with thetheromstat device and timer motor removed.

FIGURE 11 is an exploded perspective view illustrating certain of theoperating parts of the control device of FIGURE 1.

FIGURE 12 is a fragmentary front view illustrating the assembly ofcertain of the parts of the control device illustrated in FIGURE ll.

FIGURE 13 is a fragmentary, front View illustrating certain of the partsof the control device of this invention assembled together and disposedin one operating position thereof.

FIGURE 14 is a partial side view of certain operating disc constructionsof the oven control of this invention.

FIGURE 15 is a fragmentary, axial, cross-sectional View similar toFIGURE 14.

FIGURE lr6 is a schematic perspective view illustrating one operatingposition of the parts illustrated in FIG- URES 14 and 15.

FIGURE 17 is a View similar to FIGURE 16 illustrating the same parts inanother operating position thereof.

FIGURE 18 is a partial front view of certain of the assembled operatingparts of this invention disposed in one operating position thereof.

FIGURES 19-22 are views similar to FIGURE 18 respectively illustratingthe operating parts thereof in other operating positions thereof.

FIGURE 23 is a broken away, partially exploded, perspective viewillustrating another control device of this invention.

FIGURE 24 is a fragmentary, cross-sectional view illustrating anothercontrol device of this invention.

FIGURE 25 is a front view of the parts illustrated in FIGURE 24 with thecontrol knob thereof removed.

FIGURE 26 is a view similar to FIGURE 24 and illiustrates anothercontrol device of this invention.

FIGURE 27 is a fragmentary front view of the control device of FIGURE26.

FIGURE 28 is a view similar to FIGURE 26 and illustrates the controldevice in one of the operating positions thereof.

While the various features of this invention are hereinafter describedand illustrated as being particularly adaptable for providing an oven orburner control, it is to be understood that the various parts of thisinvention can be utilized singly or in any combination thereof toprovide other constructions as desired.

Therefore, this invention is not to be limited to only the embodimentsillustrated in the drawings, because the drawings are merely utilized toillustrate one of the wide variety of the uses of this invention.

Referring now to FIGURES 1 and 2, one embodiment of an improved oven orburner control device of this invention is generally indicated by thereference numeral 40 and comprises a suitable frame struct-ure 41adapted to be interconnected to any desired range or oven structure toprovide at least part of the control panel thereof, the frameconstruction 41 being readily adaptable to be interconnected to aconventional timer or clock motor 42 and a conventional thermostatdevice 43 in a manner hereinafter described, whereby the frame structure41 and the operating parts of the control device of this invention canbe manufactured by one manufacturer and be utilized with t-heconventional timer motor 42 and thermostat 43 of an oven or rangemanufacturer or the like, Of course, the range or oven manufacturer canalso make the frame structure 41 and the operating parts carriedthereby, if desired.

The particular details of the thermostat 43 do not form any part of thisinvention whereby it will suffice to state that the thermostat 43 can bean electric or mechanical operating structure which is adapted tomaintain the temperat-ure of an oven or burner at a selected temperatureupon proper positioning of a control shaft thereof in a mannerconventional in the art.

For example, the thermostat 43 illustrated in FIGURE 2 comprises anelectrically operated device receiving suitable power from a cable 44and is interconnected to a suitable burner or burners 45 by a cable 46,the burner or burners 45 being disposed in an oven 47. A suitabletemperature sensing device 48 is disposed in the oven 47 and isinterconnected to the thermostat 43 by the element 49.

In this manner, when a control knob 50 of the oven control 40 of thisinvention is rotated lfrom the off position thereof to an on positionthereof, the knob 50 rotates a control shaft 51 of the thermostat 43 tocause the thermostat 43 to operate the burner or burners 45 in such amanner that the temperature of the oven 47 is maintained at thetemperature corresponding to the temperature setting of the control knob50 in a conventional manner.

As previously set forth,` one of the features of the control device 40of this invention is to permit the housewife or the like to place foodin the oven 47 and, after determining the required cooking time andcooking temperature for the food, the housewife rotates a control knob52 from the manual position illustrated in FIGURE 1 in a clockwisedirection to indicate the desired number of hours or minutes on a dial53 that it is desired to have the oven 47 cook the food at a selectedcooking temperature.

Thereafter, the housewife moves the thermostat control knob 50 from theoff7 position illustrated in FIGURE l in a clockwise direction to thedesired temperature setting, such as 400 or the like.

Immediately, the thermostat 43 functions in a conventional manner tobring the temperature of the oven 47 up to 400 and maintains thetemperature of the oven at 400 during the entire time interval set bythe control knob 52 in a manner hereinafter described.

After the set time for the cooking temperature of the oven 47 has lapsedby the dial 53 returning to its manual position, the control device 40of this invention automatically returns the control knob 50 of thethermostat 43 in counterclockwise direction to a relatively low andnoncooking temperature, such as 140 or the like, whereby the temperatureof the oven 47 is reduced to 140 and maintained at that reducedtemperature by the thermostat 43 until the housewife turns the controlknobV 50 to the off position to terminate operation of the oven 47.

In this manner, the housewife can place food in the oven 47 and have thesame immediately cooked to prevent spoilage thereof and thereafter havethe food maintained at a warming and non-cooking temperature so thatwhen the food is subsequently removed from the oven 47 the same is at aserving temperature. Thus, the housewife or the like can be entertainingher guests even though the dinner has been completely cooked in the oven47 without worrying that the food will be overcooked or cold when it isdesired to seive the same.

While the control device 40 of this invention illustrates in FIGURES 1and 2 suitable clock arms 54 and 55 operated by the timer motor 42receiving suitable electrical current from leads 56, it is to beunderstood that the control device 40 of this invention can be utilizedwithout such clock structure as long as a suitable timer motor 42 or thelike is utilized in combination therewith as will be readily apparentwhen reference is hereinafter made to FIGURE 11.

Similarly, while the oven control 40 illustrated in FIG- URES l and 2provides a control knob 57 for operating an alarm providing timermechanism in a conventional manner, it is to be understood that thecontrol device 40 of this invention can be utilized without s-uch alarmproviding timer, if desired, the control device 40 of this inventionmerely being illustrated with other mechanism which can utilize the sametimer motor 42 to operate other mechanism as well as the temperaturereducing feature of this invention.

Further, while the various controls are hereinafter described as beingin the pattern illustrated on the control panel 60a in FIGURE 1, it isto be understood that the various control parts of the oven control 40can bearranged in other patterns as is fully illustrated in FIG- URES3-6 merely disclosing some of the other patterns that could be provided.

The particular details of the control device 40 will now be describedand reference is made to FIGURES 7 and 8 which illustrate that theconventional thermostat devices 43, normally have C-shaped or D-shapedcontrol shafts 51 projecting therefrom and operatively interconnected toa screw-like adjusting member 58 which, when rotated, controls thetemperature of the oven 47 or t-he like in la manner Well known in theart.

While the thermostat device 43 has been previously described as anelectrical device for controlling either electrical heater means or gasheater means, it is to be understood that the thermostat device 43 cancomprise a thermostat control device similar to those disclosed in thecopending application, Serial Number 833,742, filed August 14, 1959, nowU.S. Patent Number 3,132,803, whereby the thermostat device 43 isadapted to maintain the oven at a relatively low non-cooking temperatureas described in the copending application.

The frame structure 41 of the control device 40 of this inventionincludes a rear plate 59 and a front plate 60 interconnected in spacedrelation relative to each other by a plurality of pivot pillars and 127or the like secured to the rear plate 59 by nuts and carrying suitablespacing means 62 and the like to hold the plates 59 and 60 at a fixeddistance relative to each other and receive the various control parts ofthis invention therebetween, the front plate 60 being adapted to have acontrol panel 60a superimposed thereon and secured thereto in anysuitable manner.

A stepped, hollow collar 63 has one end 64 thereof projecting through abore 65 formed in the rear plate 59 and the other end 66 thereofreceived in a bore 67 formed in the front plate 60, the collar 63 beingrotatable relative to the frame means 41 for a purpose hereinafterdescribed and having an outwardly directed annular flange 68 heldagainst the inside surface of the rear panel 59 by a disc spring 69bearing against the inside surface of the front panel 60 and a shoulder70 on the collar 63.

The collar 63 has a bore 71 passing therethrough adapted totelescopically receive the control shaft 51 of the thermostat 43 in themanner illustrated in FIGURE 7, the bore '71 being provided with arecess or slot 72 adapted to receive a key or ta'b 73 formed on adisclike member 74 carried between the control shaft 51 and adjustingscrew 58 to interconnect the control shaft 51 and collar 63 together sothat the same will rotate in unison.

The thermostat 43 is pushed downwardly from the position illustrated inFIGURE 7 and has a plurality of outwardly directed ears or lugs 76thereof abut the rear surface of the rear plate 59 so that thethermostat 43 can be secured thereto by a plurality of threadedfastening members 77.

The control knob 50 is adapted to be unterconnected to the control shaft51 of the thermostat 43 in any conventional manner whereby rotation ofthe knob 50y causes like rotation of the control shaft 51, rotation ofthe control shaft 51 causing like rotation of the collar 63 and variousoperating parts of the control device 40 of this invention in a mannerhereinafter described.

It is to be understood that the thermostat device 43 includes suitablestops to prevent the control knob 50 illustrated in FIGURE l from beingrotated in a counterclockwise direction past the off position thereofand to prevent the control knob 50 from being rotated in a clockwisedirection past the broil position thereof.

As illustrated in FIGURES 7 and l1, a rst disc construction 78 issecured to a sleeve 79 loosely received around the collar 63 whereby thecollar 63 is rotatable relative to the disc construction 78.

As illustrated in FIGURE 1l, the disc construction 78 has a circularportion 80 and a cutaway portion 81 defining a notch 82 for a purposehereinafter described, the disc construction 78 carrying a rearwardlydirected, substantially cylindrical pin means 83 carrying a roller 83aon the free end thereof for a purpose hereinafter described.

As illustrated in FIGURE 7, a second disc construction 84 is disposedabout the collar 63 and comprises two substantially circular discs 85and 86, the disc 85 being iixed to the collar 63 to rotate in unisontherewith while the disc 86 is loosely received on the collar 63 andrelatively movable relative thereto for the purpose hereinafterdescribed as fully'illustrated in FIG- URE 15.

The disc 86 has a plurality of angularly disposed su'bstantially flatended teeth 87, FIGURE 1l, formed around the periphery thereof while thedisc 85 has a plurality of substantially V-shaped teeth 88 formed aroundthe periphery thereof.

The disc 86 carries a frontwardly projecting pin means 89 which passesthrough an elon-gated slot 90 formed in the disc 85 to interconnect thediscs 85 and 86 together while permitting limited movement therebetweenfor a purpose hereinafter described.

A coiled spring or mainspring 91, FIGURES 7 and ll, has the inner end 92thereof secured to the sleeve 79 carried by the disc construction 78 andthe outer end 93 thereof inter-connected to the portion of the pin means89 projecting beyond the disc 85.

In this manner, the spring 91 tends to rotate the disc 6 construction 84in a counterclockwise direction relative to the disc construction 78until the pin 89 of the disc construction 84 abuts against the pin 83carried by the disc construction 78.

When it is desired to operate the oven 47 at any selected temperaturewithout utilizing the keep-warm feature of this invention, the controlknob 52 has its dial 53 disposed in the manual position illustrated inFIGURE l whereby the thermostat control knob 50 can be rotated from theoff position thereof to any desired tem perature setting in a clockwisedirection.

As the control knob 50 is rotated in a clockwise direction, the collar63 is rotated in a clockwise direction in unison therewith and carriesthe disc construction 84 in a clockwise direction. As the discconstruction 84 is rotated in a clockwise direction, the discconstruction 78 is rotated in a clockwise direction therewith becausethe spring 91 is interconnected thereto and carries the discconstruction 78 along with the clockwise rotation of the discconstruction 84.

As will be apparent hereinafter, when the control knob 50 has beenrotated beyond the particular keep-warm temperature setting thereof,such as 140 or the like, .the controlknob 52 is rendered inoperative toset a desired time interval that the oven 47 is to be maintained at aselected temperature.

Therefore, the thermostat control knob 50 must be disposed between itsolf position and the keep-warm position thereof before the controlconstruction140 of this invention can be utilized to maintain thetemperature of the oven 47 at a selected temperature for a selected timeand thereafter reduce the temperature of the oven 47 which is to bemaintained at a selected temperature.

Therefore, the thermostat control knob 50 must be disposed between itsoff position and the keep-warm position thereof before the controlconstruction 40 of this invention can be utilized to maintain thetemperature of the oven 47 at a selected temperature for a selected timeand thereafter reduce the temperature of the oven 47 to a relatively lowwarming and non-cooking temperature.

The time-setting control knob 52 is interconnected to a shaft 94, FIGURE11, rotatably mounted between the plates 59 and 60, the shaft 94 beinginterconnected to a gear 95 having a plurality of teeth 96 disposedabout part of the periphery thereof. The periphery of the gear 95 doesnot have the teeth 96 in the area 97 thereof to prevent meshing relationof the gear 95 with an idler gear 98 carried on a shaft 99 disposedbetween the plates 59 and 60, the reduced area 97 of the gear 95 beingdisposed adjacent the gear 98 when the control knob 52 is disposed inits manual position so that the gear 98 cannot drive the gear 95.

The shaft 99 carries another gear 100 disposed in meshing relation withan enlarged gear 101 carried on a shaft 102 rotatably mounted betweenthe plates 59 and 60, of the frame means 41, the gear 101 beinginterconnected to the output shaft 103 of the timer motor 42 by asuitable gear train or the like.

For example, the timer motor 42 can have the output shaft 103 thereofcarrying a gear 104 disposed in meshing relation with the gear 101 asillustrated in FIGURE ll, the timer motor 42 driving a suitable clockstructure or not as desired.

The shaft 99 carrying the idler gear 98 is transversely movable relativeto the plates 59 and 60 of the frame means 41 and is normally urgedupwardly by a tension spring 105 to tend to hold the idler gear 98 indriving relation with the teeth 96 of the gear 95 when the gear 95 isrotated to a position thereof to permit the teeth 96 to be disposed inmeshing yrelation with the gear 98.

However, when the control knob 52 is set in the manual position thereof,the recessed portion 97 of the gear 95 is disposed adjacent the gear 98whereby operation of the timer motor 42 does not drive the gear 95.

Should the control knob 52 be rotated to a time indicating positionthereof, the gear 95 is likewise rotated with the teeth 96 thereofcamming the idler gear 98, in opposition to the force of the tensionspring 105, away from meshing relation with the teeth 96 until the gear95 is set in the desired position thereof. Thereafter, the spring 105brings the idler gear 98 into meshing relation with the teeth 96 of thegear 95 and whereby the timer motor 42 drives the gear 95 until therecessed portion 97 thereof is disposed adjacent to the gear 98, atwhich time, the dial 53 is disposed in the manual position thereof.

Thus, by a suitable gear arrangement, the gear 95 can be set to rotatethrough any desired period of time, such as between zero and eight hoursor the like.

The gear 95 carries a substantially circular cam member 106 on the rearside thereof, the cam member 106 having a camming notch 107 formedtherein.

A substantially L-shaped lever 108 has one end 109 thereof pivotallymounted on a pivot pillar 110 extending between the plates 59 and 60 ofthe control device 40 and being secured to the rear plate 59 by a nutwhereby the other end 111 of lever 108 is adapted to be moved to theright or the left about the pivot pillar 110.

The elbow 112 of the lever 108 is adapted to be disposed in the cammingnotch 107 'of the cam 106 when the control knob 52 is disposed in themanual position thereof.

However, when the control knob 52 is rotated to a time-indicatingposition thereof, the cam 106 is rotated in unison therewith in aclockwise direction and cams the lever 108 in a counterclockwisedirection to move the end 111 of the lever 108 to the right for apurpose hereinafter described.

The lever 108 is held in its counterclockwise position by the cam 106 aslong as the gear 95 is being rotated in a counterclockwise direction bythe gear 98. However, as soon as the gear 95 reaches its manualposition, the elbow 112 of the lever 108 is pulled into the notch 107 ofthe cam 106 by a tension spring 134 having one end thereof attached tothe lever 108 and the other end thereof attached to the frame means 41whereby the lever 108 is rotated in clockwise direction to move the end111 thereof to the left for a purpose hereinafter described.

A pivot pin 113, FIGURE 11, extends between the plates 59 and 60. A pairof pawls 114 and 115 are respectively pivotally carried by the pivot pin113 whereby the pawl 114 is adapted to have a tooth 116 thereof receivedin the recesses between the teeth of the discs 85 and 86 to preventcounterclockwise rotation of the disc construction 84 in a mannerhereinafter described. Similarly, the pawl 115 has a tang or tooth 117adapted to be received in the notch 82 of the disc construction 78 toprevent clockwise rotation thereof for a purpose hereinafter described.

A pin 118 projects outwardly from the end 111 of the lever 108 and isadapted to engage the pawl 115 whereby movement of the end 111 of thelever 108 to the right, upon clockwise rotation of the cam 106, causesthe pin 118 to move the pawl 115 to the right to have the tang 117thereof received in the path of the notch 82 of the disc construction78, the pawl 115 being moved to the right in opposition to a force of atension spring 119 having the end thereof interconnected thereto and theother end thereof interconnected to the lever 108.

The pawl 114 has a forwardly directed pin 120 extending therefrom andpassing through a circular aperture 121 formed in the end 111 of thelever 108.

A spring 122 is coiled about the pin 118 and has one end 123 thereofinterconnected to the lever 108 and the other end 124 thereof bearingagainst the pin 120 carried by the pawl 114 whereby the spring 122 tendsto move the pawl 114 to the right in a counterclockwise direction aboutthe pivot pin 113.

However, when the lever 108 is disposed in the notch 107 of the cam 106,the pawl 114 is prevented from engagement with the disc construction 84because the spring 122 pushes the pin 120 only against the righthandside wall ofthe aperture 121 in the lever 108.

When the control knob 52 is rotated to a time-indicating positionthereof, the end 111 of the lever 108 is moved to the right whereby thespring 122 likewise moves the pawl 114 to the right into engagement withthe disc construction 84, the pin 118 moving the pawl 115 to the rightin unison with the pawl 114.

A substantially L-shaped lever 125 has one end 126 thereof pivotallymounted on a pivot pillar 127 disposed between the plates 59 and 60 ofthe frame means 41 and secured to the rear plate by a nut, the L-shapedlever 125 normally being urged in a counterclockwise direction about theshaft 127 by a tension spring 128 having one end 129 interconnected to aprojection 130 formed on the other end 131 of the lever and the otherend thereof interconnected to end 109 of the lever 108.

The lever 125 has a camming surface 132 disposed below the elbow 133thereof for a purpose hereinafter described.

When it is desired to utilize the thermostatic control device 40 of thisinvention to regulate the temperature of the oven 47 without utilizingthe keep warm feature of this invention, the control knob 52 is disposedin its manual position and the thermostatic control knob 50 is disposedin its off position as illustrated in FIG- URE 1.

When the control knobs 52 and 50 are respectively disposed in theirmanna and off positions, the disc constructions 78 and 84 are disposedin the position illustrated in FIGURE 18 whereby the pin 83` and roller83a of the disc construction 78 is disposed beyond the elbow 133 of thelever 125 and the pin 89 of the disc construction 84 has passed beyondthe camming surface 132 of the lever 125 to hold the lever 125 to theright in opposition to the force of the tenison spring 128.

The housewife or the like subsequently turns the control knob 50 in aclockwise direction to the desired temperature setting, such as 300. Asthe control knob 50` is rotated in a clockwise direction, the controlknob 50 through the thermostat control shaft 51 rotates the collar `63and thus the disc construction 84 in a clockwise direction. As the discconstruction 84 is rotated in a clockwise direction, the main spring 91causes the disc construction 78 to also rotate in a clockwise directionin unison with the disc construction 84.

As the disc construction 78 is rotated in a clockwise direction past the140, keep-warm setting of the control knob 50, the circular peripheralsurface of the disc construction 78 moves into the path of movement ofthe tang 117 of pawl 115 whereby an attempt to rotate the control knob52 from the manual position thereof to any time setting position isprevented by the camming surface 80 of the disc construction 78 becausethe pawl cannot be pushed to the right a suicient distance to clear theelbow 112 of the lever 108 from the notch 107 of the cam member 106.

Therefore, the control knob 50 must be disposed in its off position orbetween its olf position and the keepwarm setting thereof before thecontrol knob 52 can be rotated from its manual position to sometime-indicating position.

As the pins 83 and 89 and the roller 83a of the disc constructions 78and 84 pass beyond the cam area of the lever in a clockwise directionwhile the temperature setting of the control knob 50 is increased, thelever 125 moves in to bear against a limit rod (not shown) whichprevents further movement thereof in a counterclockwise direction aboutits pivot pillar 127.

Thus, it can be seen that the control knob 50 can be utilized withoutthe control knob 52 to set a desired tem- 75 perature for the oven 47whereby the thermostat device 9 43, through the proper rotation of thecontrol shaft 51, maintains the temperature of the oven 4'7 at thetemperature setting indicated by the control knob 50.

When it is desired to turn off the oven 47, the control knob 50 isrotated in a counterclockwise direction back to its oi-li position.

As the control knob 50 is rotated back to its off position, the roller83a of the disc construction 78, while being rotated in acounterclockwise direction, comes into contact with the camming surface132 of the lever 125 while the pin 39 of the disc construction 84 comesinto contact with the camming surface 132 of the lever 125 so thatfurther counterclockwise rotation of the disc constructions 78 and 84causes the pin 89 to cam against the camming surface 132 of the lever125 to pivot the lever 125 in a clockwise direction about its pivotpillar 127 to permit the pins 83 and 89 and roller 83a to assume theposition illustrated in FIGURE 18 when the control knob 50' is disposedin its off position.

When it is desired to utilize the control device 40 to maintain thetemperature of the oven 47 at a desired cooking temperature for apredetermined length of time, and thereafter, reduce the temperature ofthe oven 47 to a warming and non-cooking temperature, the control knob58 must be disposed in its off position or at any ternperature settingthereof below the keep-warm position thereof, such as 140.

Thereafter, the control knob 52 is rotated in a clockwise direction fromits manual position to any desired time indicated setting thereof, forexample, four hours or the like.

As the control knob 52 is moved from its manual position to atime-indicating position thereof, the gear 95 and cam 105 mounted on theshaft 94 of the control knob 52 are rotated in a clockwise directionwhereby the gear teeth 96 of the gear 95 are placed in meshing relationwith the idler gear 98 and, simultaneously, the cam 106 has the notch107 thereof clearing the elbow 112 of the lever 108, to cause the lever108 to rotate in a counterclockwise direction about its pivot pillar110.

When the end 111 of the lever 108 is moved to the right by the carn 106,the pin 118 carried by the end 111 of the lever 108 moves the pawl 115in a counterclockwise direction whereby the tang 117 thereof is disposedin the path ot the notch 82 of the disc construction 78 as illustratedin FIGURE 20.

Simultaneously, the spring 122 acting against the pin 128 carried by thepawl 114 causes the pawl 114 to rotate in a counterclockwise directionabout the pivot pin 113 bringing the tang 116 thereof into engagementwith the disc construction 84.

Thereafter, the control knob 50 is rotated in a clockwise direction tothe desired temperature setting for the oven 47, such as 300 or thelike.

However, as the control knob 50`v is rotated in a clockwise directionfrom its off position thereof, the disc constructions 78 and 84 rotatein unison therewith a clockwise direction until the notch 82 of the discconstruction 78 comes into contact with the tang 117 of the pawl 115whereby the pawl 115 prevents further clockwise rotation of the discconstruction 78 in the manner illustrated in FIGURE 2l.

The teeth 87 and 88 on the discs 85 and 86 of the disc construction 84are so constructed and arranged, that the tang or tooth 116 of the pawl114 does not prevent clockwise rotation of the disc construction 84 andthe disc 85 and 86 merely cam the pawl 114 in a clockwise directionabout the pivot pin 113` in opposition to the force of the tensionspring 124- to permit such clockwise movement of the disc construction84.

When the disc construction 78 has the notch 82 thereof disposed againstthe tang 117 of the pawl 115, the pin 83 of the disc construction 78 isdisposed slightly below the elbow 133 of the lever 125 in the mannerillustrated in FIGURE 21 for a purpose hereinafter described.

After the disc construction 78 has been prevented from further clockwiserotation by the pawl 115, further clockwise rotation of the control knob50 causes the disc construction 84 to continue to rotate in a clockwisedirection in the manner illustrated in FIGURE 22 whereby the main spring91 is being continuously wound up because the disc construction 78remains motionless while the disc construction 84 continues to berotated in a clockwise direction.

When the control knob 50' has been rotated in a clockwise direction tothe desired temperature setting, such as 300 as illustrated in FIGURE22, the tooth 116 of the pawl 114 is received between the teeth 87 ofthe disc 86 and prevents the spring 91 from rotating the discconstruction 84 in a counterclockwise direction whereby the pawl 114holds the control shaft 51 at the desired temperature setting thereof.

However, should the housewife or the like accidentally advance thecontrol knob 50 in a clockwise direction past the desired temperaturesetting, the disc construction 84 is so constructed and arranged thatthe control knob 50 can be advanced backwardly in a counterclockwisedirection to the desired temperature setting.

For example, should the housewife desire that the control knob 50 bedisposed in the 300 position thereof and accidentally advances thecontrol knob 50 to the 400 position thereof, the housewife then graspsthe control knob 50 and rotates the same back in a counterclockwisedirection to the 300 setting thereof.

To accomplish this function of the disc construction 84, reference isnow made to FIGURE 16 wherein it can be seen that as the control knob 50is advanced in a clockwise direction, the disc 85, being fixedly securedto the collar 63, is likewise rotated in a clockwise direction. However,since the disc 86 of the disc construction 84 is loosely mounted on thecollar 63, the disc 85 is adapted to be slightly rotated relative to thedisc 86 until the lefthand side wall of the slot engages the pin 89carried by the disc 86 whereby further clockwise rotation of the disc 85by the control knob 50 causes like clockwise rotation of the disc 86.

When the discs 85 and 86 of the disc construction 84 are disposed in theposition as illustrated in FIGURE 16, the tang 116 of pawl 114 isadapted to be seated between the teeth 87 of the disc 86 under the forceof 4the compression spring 122 when clockwise rotation of the controlknob 50 is terminated because the teeth 88 of the disc 85 when disposedin the position illustrated in FIGURE 16 permit the tang 116 of the pawl114 to be received between the teeth 87 of the disc 86 whereby the pawl114 prevents the spring 91 from rotating the disc construction 84 in acounterclockwise direction.

While the disc 85 is being rotated in a clockwise direction bythecontrol knob 50, the disc 86 is prevented from being rotated relativetherewith by the spring 91 until the pin 89 engages the left-hand wallof the slot 9i) in the disc 85, whereby further clockwise movement ofthe disc 85 causes the disc 86 to move in unison therewith in aclockwise direction in the above manner.

Thus, when further clockwise rotation of the control knob 50 isterminated, the pawl 114 prevents counterclockwise rotation of the discconstruction 84 in the above manner.

However, should the housewife or the like grasp the control knob 50 torotate the same in a counterclockwise direction back to the desiredtemperature setting for the oven 47, initial counterclockwise movementof the control knob 50 causes the disc 85 to rotate in acounterclockwise direction relative to the disc 86 because the pawl 114is holding the disc 86 from such counterclockwise rotation and theelongated slot 90 in the disc 85 permits such relative movement.

However, slight movement of the disc 85 in a counterclockwise directionrelative to the disc 86 causes the teeth 88 of the disc 85 to cam thetang 116 of the pawl 114 in a clockwise direction about its pivot pin113 to free movement of the disc 86 in a counterclockwise direction.

Thus, the disc construction 84 can be advanced back- Wardly in acounterclockwise direction `to the desired temperature setting of thecontrol knob 50.

When the disc construction 84 is rotated back to the desired temperaturesetting of the control knob 50, the spring 91 causes the disc 86 to befurther rotated in a counterclockwise direction relative to the disc 85,now being held stationary by the collar 63, until `the pin 89 abuts theleft-hand wall of the slot 90 whereby the discs 85 and 86 again assumethe position illustrated in FIG- URE 16 so that the tang 116 of the pawl114 can be again pushed between lthe teeth 87 of the disc 86 by thespring 122 and prevent counterclockwise movement of the discconstruction 84 relative to the disc construction 78.

While the above operation of rotating the control knob 50 from a highsetting thereof to a lower setting thereof has been described inconnection with accidently moving the control knob 50 to a hightemperature setting thereof, it is to be understood that the sameprocedure is followed should it be desired to have the oven at a hightemperature during part of the cooking time and, thereafter, manuallyreduce the temperature setting of the control knob 50 to a lowertemperature setting before the temperature setting is automaticallyreduced.

Therefore, it can be seen that the control knob 52 can set the desirednumber of hours and minutes it is desired to maintain the oven 47 at asubsequent cookingr temperature setting of the control knob 50 and thenthe temperature of the oven 47 can be set at the desired temperaturesetting thereof by the control knob 50.

Once the control knobs 52 and 50 have been set in the above manner, thehousewife need not bother the control device 40 because the samefunctions completely automatically in the following manner.

In particular, the timer motor 42, through the gear train structure 104,101, 100 and 98, continues to rotate the gear 95 in a counterclockwisedirection for the period of time set by the dial 53 while the thermostat43 maintains the temperature of the oven 47 at the desired temperaturesetting to the control knob 50 in a conventional manner.

When the gear 95 has been driven back to the position to permit therecessed area 97 thereof to be disposed against 'the idler gear 98,further rotation of the gear 94 is prevented and the desired number ofhours and minutes for maintaining the oven 47 at the desired temperaturesetting has been reached.

When the gear 95 has been driven back to the manual position thereof,the cam 106 is rotated in unison therewith `and permits the elbow 112 ofthe lever 108 to be drawn into the notch 107 thereof under the influenceof the tension spring 134 whereby the lever 108 is rotated in aclockwise direction about its pivot pillar 110 to move the end 111 ofthe lever 108 to the left. As the end 111 of the lever 108 is moved tothe left, the right-hand wall of the aperture 121 in the end 111 thereofpulls the pin 120 to the left to carry the pawl 114 away from the discconstruction 84.

As the tang 116 of the pawl 114 is pulled away from the teeth 87 of thedisc 86, the spring 91 causes counterclockwise rotation of the discconstruction 84 whereby counterclockwise rotation of the discconstruction 84 causes like counterclockwise rotation of the collar 63and the control knob 50 back toward the off position thereof.

During the counterclockwise rotation of the disc construction 84 by thespring 91, the disc construction 78 remains stationary and holds thepawl 115 in engagement with the notch 82 thereof by the force of themainspring 91 tending to rotate the disc construction 78 in a clockwisedirection whereby the pawl 115 remains in engagement with the discconstruction 78 in opposition to the force of the spring 119 tending topull the same `to the 12 left because the pin 118 of the lever 108 hasbeen previously moved to the left.

In this manner the disc construction 78 remains stationary While thedisc construction 84 is being rotated in a counterclockwise directon bythe spring 91.

As the disc construction 84 is being rotated in a counterclockwisedirection by the spring 91, the pin 89 thereof eventually comes intocontact with the roller 83a of the pin 83 of the disc construction 78 inthe manner illustrated in FIGURE 21 to tend to rotate the discconstruction 78 in a counterclockwise direction therewith.

However, only slight counterclockwise rotation of the disc construction78 is permitted from the position illustrated in FIGURE 2l because thepin 89 of the disc construction 84 moves the roller 83a of the discconstruction 78 into engagement with the elbow 133 of the lever 125 inthe manner illustrated in FiGURE 20 whereby the lever 125 preventsfurther counterclockwise rotation of the disc constructions 78 and 84.In this manner, the control shaft 51 of the thermostat 43 is nowdisposed and held in a noncooking and warming temperature positionthereof, such as 140 or the like.

As the disc construction 78 is moved from the position illustrated inFIGURE 21 to the position illustrated in FIGURE 20, the pawl is releasedfrom engagement with the disc construction 78 whereby the tension spring119 can pivot the pawl 115 in a clockwise direction about its pivot pin112'@` into engagement with the pin 118, carried by the lever 108.

Thus, it can be seen that when the desired number of hours has beenreached for the cooking setting of the oven 47, the control device 40 ofthis invention automatically reduces the temperature setting of the oven47 to a warming and noncooking temperature whereby the temperature ofthe food in the oven 47 will be held at a serving temperature but willnot be further cooked by the oven 47.

Thus, after the food has been cooked, the oven 47 maintains the same vata serving temperature regardless of the length of time the food remainsin the oven until the housewife manually returns the control knob 50 toits off position.

To return the control knob 50 from the keep-warm temperature settingthereof to its off position, the housewife merely grasps the controlknob 50 and rotates the same in a counterclockwise direction,counterclockwise rotation of the control knob 50 causing the discconstruction 84 to rotate in a counterclockwise direction and have theroller 83a cam against the front inside surface of the lever to move thelever 125 in a clockwise direction about its pivot pillar 127 to permitthe pin 83 and roller 83a of the disc construction 78 to clear the elbow133 thereof and be moved back to the position illustrated in FIGURE 18.

Thus, it can be seen that the control device 40 of this inventionpermits the oven 47 to be utilized in a conventional manner without anytime setting feature thereof. Further, the control device 40 of thisinvention permits the housewife to place food in the oven and set thecontrol knob 52 to the desired number of cooking hours for the food and,thereafter, set the control knob 50 at the desired cooking temperaturefor the oven 47 whereby the oven control cooks the food at the desiredtemperature through a desired number of hours and minutes. Thereafter,the control device 40 reduces the temperature of the oven to a lowwarming and non-cooking temperature to maintain the food at a servingtemperature without further cooking of the same until the housewiferemoves the food from the oven 47.

While the non-cooking and keep-warm temperature of the oven 47 has beenheretofore mentioned as being approximately it is to be understood thatthe lever construction 125 can be so constructed and arranged that thesame provides a different keep-warm temperature setting of thethermostat 43 by varying the shape of the 13 lever 125, the temperatureof 140 merely being exemplary of such a non-cooking and keep-warmtemperature setting for the oven 47.

Further, means can be provided for selectively adjusting the keep-warmtemperature setting of the thermostat 43.

In particular, reference is made to FIGURE 23 wherein anotherthermostatic control device of this invention is generally indicated bythe reference numeral 135 which has parts thereof substantiallyidentical to the thermostatic control 40 previously described exceptthat the thermostatic control 135 has means for adjusting the desiredtemperature setting of the keep-warm position of the lever 125.

For example, the pivot pin 127a of the control device 135 issubstantially the same as the pivot pillar 127 for the lever 125 of thecontrol device 40 previously described except that the pivot pin 127a isnot fixed relative to the front and rear plates of the control device135 in the manner of the pivot pillar 127.

Instead, the pivot pin 127a is carried by an arm 136 of a lever 137pivotally mounted to the frame construction 41 of the control device 135by a pivot pin 138.

In this manner, pivotal movement of the lever 137 about its pivot pin138, which is coaxial with the collar 63, changes the position of thepivot pin 127a whereby the lever 125 will stop counterclockwise rotationof the disc constructions 78 and 84 at a different position to hold thecontrol shaft 51 of the thermostat 43 at a different temperature settingthereof.

The arm 136 of the lever 137 has a plurality of teeth 139 disposed inmeshing relation With the teeth of a gear 140 disposed in meshingrelation with a larger gear 141.

The gear 141 is interconnected to a shaft 142 interconnected to acontrol knob 143 graduated in different temperature settings thereofwhereby rotation of the control knob 143 to the desired temperaturesetting thereof causes movement of the lever 137 through rotation of thegears 141 and 140 to set a new position for the lever 125 to haltcounterclockwise movement of the disc constructions 78 and 84 after thesame have been released from the high cooking temperature settingthereof and are to be returned to a low temperature setting thereof.

Thus, it can be seen that the control knob 143 can select a desiredreturn setting of the thermostat 43 in a relatively simple manner.

Another means for adjusting the control device of this invention toreturn to any desired temperature setting of the thermostat 43 after thetimer has returned disc 53 to its manual position, is generallyindicated by the reference numeral 144 in FIGURES 24 and 25 wherein thebasic parts of the control device 144 are substantially the same as thecontrol device 40 previously described and indicated by like referencenumerals followed by the reference letter b.

However, the collar 63b of the control device 144 is not interconnectedto the control shaft 51b by the plate 74 previously described.

Instead, an annular plate 145 is keyed to the collar 63]) in anysuitable manner whereby the rotation of the collar 63b causes likerotation of the other plate 145 or vice versa.

The plate 145 has an elongated sector slot 146 formed therein whereinthe left-hand wall 147 of the plate 145 has a plurality of long teeth148 formed thereon and the right wall 149 of the slot 146 has aplurality of short teeth formed thereon.

Another annular plate 151 is disposed adjacent to the plate 145 and ismovable relative thereto, the plate 151 being suitably keyed orotherwise secured to the control shaft 51b in any suitable manner.

The plate 151 has a suitable slot 152 formed therein and adapted toreceive an adjusting pin 153 having a bifurcated end 154 projectingoutwardly beyond the plate 151 and being received in a suitable cavity155 formed in the control knob 5017 suitably interconnected to thecontrol shaft 51b.

The pin 153 carries a gear 156 on the rear end thereof, the gear 156normally being disposed in meshing relation with teeth 148 and teeth 150by a leaf spring 157.

In this manner, the control knob 50b is interconnected to the collar 63hbecause the plate 151 is splined to the plate by the pin 153 when thepin 153 is disposed in the position illustrated in FIGURE 24.

When it is desired to adjust the keep-warm setting of the control device144 to another temperature setting thereof, the control knob 5011 isremoved from the controlled shaft 51b and a screwdriver or the like isinserted in the bifurcated end 154 of the pin 153 whereby the pin 153can be depressed in the slot 146 rearwardly against the opposition ofthe force of the leaf spring 157 to clear the gear 156 from the teeth150.

When the gear 156 has been cleared from the teeth 150, the pin 153 isrotated in the proper direction by the screwdriver or the like to causethe gear 156 thereof to react against the teeth 148 of the plate 145 androtate the plate 145 relative to the plate 1511, whereby the collar 63his rotated to a new position relative to the control shaft 51b.

Thereafter, the screwdriver is released from the pin 153 whereby theleaf spring 157 returns the pin 153 to the position illus-trated inFIGURE 24 so that the gear 156 if locked from rotational movementthereof by the gear teeth 148 and 1:50 and interconnected to the plate145 to plate 151. In this manner, rotation of the control knob 5017causes rotation of the control shaft 51b and like rotation of the collar63h in the manner previously described to perform the desired functions.

Thus, it can be seen that the adjusting pin 153 of the control device144 can be utilized to selectively change the return setting of thecontrol knob 50b by the disc constructions 78 and 84 when a desirednumber of cooking hours has been reached.

Another control device of this invention is generally indicated by thereference numeral `158 in FIGURES 26-28 and has the basic parts thereofformed in substantially the same manner as the control device 40previously described whereby like part-s thereof are indicated by likereference numerals followed by the reference letter c.

As in the control device 144 previously described, the control shaft 51Cof the control device 158 is not interconnected to the collar 63C by theplate 74 in the manner of the control device 40 previously described.

Instead a plate 159 is keyed or otherwise secured to the c-ollar 63e inany suitable manner, the plate 159 having 'a slot 160 formedtherethrough and Areceiving a locking tang 161 carried on a springmember 162 secured to the plate 159 by rivets 163 or the like. Thespring lever 162 has a handle and temperature indicating portion 164extending beyond the control knob 50c in the manner illustrated inlFIGURE 27 whereby the pointer 164 indicates the temperature at whichthe control knob 50c will return to a keep-Warm setting thereof.

Another plate 165 is disposed adjacent to the plate 159 and is movablerelative thereto, the plate 165 having a slot 166 formed therein andprovided with long teeth -167 on one side thereof and shorter teeth 168on the other side thereof.

A pin 169 is disposed in a bore 170 formed through the control knob 50cand registering with the slot 166 in the plate 165, the pin 169 having agear 171 formed on the rear end thereof and normally disposed in meshingrelation with the teeth 116-7 and 168 by a leaf spring 172 whereby thepin 169 splines the plate 165 to the control knob 50c which isinterconnected to the control shaft 51C.

The plate 165 is interconnected to another plate 165a which has aplurality of radially and circumferentially disposed slots 173 formedtherein which are respectively adapted to receive the tang `161 of thespring lever 162 when the spr-ing lever 162 is disposed in the positionillustrated in FIGURE 26. In this manner, the p-late 165 isinterconnected to the plate 159 by the tang 161 so that the controlshaft 51C is xed relative to the collar 63C.

When the control device 158 has been installed in combination with anoven or the like, the oven is operated in the above manner to cause thecontrol knob 50c to return to its keep-warm position.

When the control knob 50c has been returned to its keep-warm position,the field service man places a test thermocouple in the oven 47 todetermine what is the actual temperature that the control knob 50c ismaintaining the oven. For example, should it be found that theindicating pointer 164 is disposed at 140, and the oven is actuallybeing maintained at 150, the eld service man removes a spring retainer174 from the control knob 50c and inserts a screwdriver in thebifurcated end 175 of the pin 169 to depress the same rearwardly and inopposition to the force `of the leaf spring 172 to cause the gear 171 toclear the teeth 168.

When the gear 171 has cleared the teeth 168 of the plate 165, the gear171 can be rotated against the teeth 167 by the screwdriver and causelike rotation of the plates 165 and 159 relative to the `control knob50c.

`In this manner, the pointer 165 and collar 63C are moved relative tothe control shaft 51C until the pointer 164 indicates a temperature thatcorresponds to the test thermocouple.

Thereafter, the screwdriver is released and the spring 172 returns gear171 into locking engagement with the teeth 167 and 168 whereby thecontrol knob 50c is fully interconnected to the plate 1165.

Subsequently, the housewife can adjust the keep-warm temperature settingby merely grasping the indicating handle 164 and pushing rearwardlythereon in the manner illustrated in FIGURE 28 to clear the tang 161from its respective slot 173 in the plate 165g. With the tang 161 clearof the plate 165a, the housewife then rotates the control knob 50c inthe desired direction to bring the desired temperature setting thereofadjacent the indicating pointer 164.

The housewife then lets the tang 161 enter the registering slot 173 Iinthe plate 165:1 to interconnect the plates 41'59 and 165 togetherwhereby the relative positions between the control shaft 51e and thecollar 63C have been 'adjusted so that the disc constructions 78 and 84will return the control shaft 50c to a different keepwarm temperaturesetting thereof.

Therefore, it can be seen that various control devices and the like havebeen provided by this invention wherein a burner or oven can -bemaintained at a selected temperature for a selected period of time andthereafter have the temperature setting thereof reduced to apredetermined or selected temperature whereby food can be maintained ata serving temperature without further cooking thereof for any desiredlength of time.

Further, certain of the control devices of this invention have means forselecting a desired keep-warm temperature setting.

While the form of the invention now preferred has been disclosed asrequired by the statutes, other forms may be used, all coming within thescope of the claims which follow.

What is claimed is:

11. In combination, frame means, a rotatable collar means rotatablymounted to said frame means and being adapted to be interconnected to acontrol shaft means of an open thermostat means whereby said collarmeans and said control shaft means will be adapted to move in unison, aring gear-like member rotatably mounted to said frame means and havinginterconnecting means to interconnect the same to said collar means torotate therewith, spring means having one end interconnected to saidframe means and the other end thereof interconnected to said ring -gea-rmeans whereby Irotation of said ring gear-like means in one -directionstores energy in said spring means to tend to return said ring gear-likemeans and said collar means in the opposite rotational direction, andmeans carried by said frame means to engage said ring gear-like meansand prevent the same from rotating in said opposite direction untilafter the occurrence of an event.

2. A combination as set forth in claim 1 wherein said last-named meanscomprises a pawl member pivotally mounted to said frame member.

3. A combination as set forth in claim 2 and including another springmeans carried by said frame means and tending to pivot said pawl memberin a direction to engage said ring gearlike member and tend to preventsaid rotation thereof in said opposite direction.

`4. A combination as set forth in claim 3 and including means forpivoting said pawl member in a direction away from said ring gear-'likemem-ber after the occurrence of said event to permit said first-namedspring means to rotate said ring gear-like member and said collar meansin said opposite direction.

5. A combination as set forth in claim 4 and including means carried Ibysaid frame means stopping the rotation of said ring gear-like member andsaid collar means in said opposite direction before said collar meansreaches its off position setting.

6. A combination as set forth in claim 1 wherein said collar means hasan off position, a low temperature position f-o-r said thermostat meansand a cooking temperature range position for said thermostat, saidspring means being adapted to rotate said ring gear-like member and saidcollar means from a cooking tem-perature position of said collar meansto said low temperature position of said collar means after theoccurrence of said event.

7. A combination as set forth lin claim 6 and including a timer meanscarried by said frame means to control the operation of said last-namedmeans that engages said ring gear-like member.

8. A combination as set forth in claim 7 and including a lever pivotallycarried by said frame member and being pivoted in one direction after alapse of a time period set by said timer means to disengage saidlast-named means from said ring gear-like member.

r9. A combination as set forth in claim 8 and including a cam memberrotatably carried by said frame means and operatively interconnected tosaid timer means to be rotated thereby when said timer means is set fora predetermined time period, said cam member controlling the pivotmovement of said lever.

10. A combination as set forth in claim 9` and including another springmeans carried by said frame means and tending to maintain said lever inengagement with said cam member.

References Cited UNITED STATES PATENTS 1,397,407 11/1921 yDodge 236-472,471,862 5/ 1949 Candor 23 6-46 2,545,846 3/1951 IDunn 236-46 2,801,7998/ 1957 McCollooh 236-46 42,914,644 r11/'1959 Holtkamp 236-15 X3,032,636 5/1962 Schauer 236-46 X 3,123,298 3/1964 Wolife 236-46 WILLIAMI WYE, Primary Examiner.

